1. Field of the Invention
The present invention relates to a circuit breaker field and, more particularly, to an apparatus for preventing withdrawing or inserting of a carriage in a circuit breaker capable of preventing a breaker body from being inserted into or withdrawn from a cradle while a circuit breaker is being input by interworking with an opening and closing operation of the circuit breaker, to thereby secure stability of the circuit breaker and prevent damage to the circuit breaker.
2. Description of the Related Art
In general, a vacuum circuit breaker (referred to as a ‘circuit breaker’, hereinafter) is a protection device for automatically breaking power quickly when there is a fault in a power system as well as transmitting and receiving, switching and stopping power by using a vacuum interrupter as an arc extinguishing medium. Namely, the circuit breaker rapidly spreads and extinguishes an arc product, which is generated during an opening and closing in case of a normal load and when an accident current is broken, to quickly separate a circuit to thereby protect the circuit and the device.
The circuit breaker generally includes a cradle, a breaker main body, a carriage, and auxiliary devices. Here, the carriage includes various mechanic devices integrally coupled with the breaker main body and selectively move the breaker main body to the cradle.
In order to operate the circuit breaker, the breaker main body must be electrically connected with the cradle. Namely, the carriage must be completely moved to the cradle and respective contact points of the breaker main body integrally coupled with a front side of the carriage must be completely bound with the cradle to perform a closing operation. However, if the carriage is inserted and withdrawn while the circuit breaker is being closed, a serious safety accident would occur or the device would be damaged, so an apparatus for preventing inserting and withdrawing of carriage is required to prevent the carriage from being inserted or withdrawn while the circuit breaker is being closed.
FIGS. 1 to 4 illustrate an apparatus for preventing inserting and withdrawing of a carriage of the related art circuit breaker.
As shown in FIGS. 1 to 4, the related art circuit breaker includes a cradle 1, a breaker main body 2, a carriage 3 and auxiliary devices.
A lead screw 32 for adding a rotational force to enable the carriage to move in a forward and backward direction is installed within a casing 31, and a nut 33 is threaded with the lead screw in order to provide a moving force to the carriage upon receiving the rotational force of the lead screw 32. Namely, in the related art withdrawing and inserting preventing apparatus, the rotation of the nut 33 is controlled (regulated or managed) in order to prevent the carriage 3 from being unnecessarily inserted or withdrawn during a closing operation.
The withdrawing and inserting preventing apparatus includes a fixed frame 34 installed near the nut 33, clamping members 35 installed at both sides of the nut 33, a horizontal moving plate 36 for moving the clamping members 35 up and down in a state of being in contact with the clamping member 35, and a horizontal moving plate manipulation unit 37 coupled with one side of the horizontal moving plate 36 and providing a moving force to allow the horizontal moving plate 36 to be horizontally moved selectively.
A roller 38 is installed at one end of the clamping member 35 and a stopping piece 39 is integrally formed at the other end of the clamping member 35. The stopping piece 39 is selectively inserted into a stopping recess 33a formed on the nut 33 to control the rotational force of the lead screw 32.
The horizontal moving plate 36 selectively inserts or releases a roller 38 of the clamping member 35 into or from a sliding recess 36a formed at the horizontal moving plate 36 by means of the horizontal moving plate manipulation unit 37, to thus allow the stopping piece 39 of the clamping member 35 to be clamped to a stopping recess 33a of the nut 33 or released therefrom.
Here, the horizontal moving plate manipulation unit 37 includes a first link member 41 having one end directly hinge-coupled to the horizontal moving plate 36, a second link member 42 having one end hinge-coupled to the other end of the first link member 41 and the other end hinge-coupled to the casing 31, a manipulation pin 43 installed to be vertically moved according to a pressing manipulation in a state of being hinge-coupled to an intermediate portion of the second link member, a guide frame 44 for guiding a vertical movement in a state that the manipulation pin 43 is inserted therein, and a coil spring 45 installed between the manipulation pin 43 and the guide frame 44.
In the horizontal moving plate manipulation unit 37, the manipulation pin 43 is protruded upwardly usually by virtue of an elastic force of the coil spring 45 as shown in FIG. 3. Thus, the second link member 42 hinge-coupled therewith is also positioned at an upper side, and because the second link member 42 is hinge-coupled with the first link member 41, the horizontal moving plate 36 is moved at the right side on the drawing by the first link member 41. In this case, as shown in FIG. 4, the roller 38 of the clamping members 35 installed at both sides of the nut 33 is in a state of being deeply inserted in the sliding recess 36a of the horizontal moving plate 36, and accordingly, the stopping piece 39 of the clamping member 35 is inserted in the stopping recess 33a of the nut 33, preventing a rotation of the nut 33. In this state, because the nut 33 is fixed, the carriage 3 can be movable as the lead screw 33 is rotated in one direction.
Meanwhile, when the circuit breaker is in a state of completely closed in the cradle 1 (or while being closed), the circuit breaker must be fixed such that it cannot be withdrawn or inserted. In this case, a rotating piece 46 installed at an upper side of the manipulation pin 43 is rotated clockwise on the drawing, pressing the manipulation pin 43, and in a state that the manipulation pin 43 is moved downwardly, the first and second link members 41 and 42 coupled with the manipulation pin 43 are unfolded in a straight line, pushing the horizontal moving plate 36 to the left side on the drawing.
Then, the roller 38 of the clamping member 35 inserted in the sliding recess 36a of the horizontal moving plate is pushed out in a forward/backward direction along the sliding recess 36a, and the clamping member 35 is released from the stopping recess 33a of the nut 33. Accordingly, the nut 33 is rotated together with the lead screw 32, preventing the carriage 3 from moving. IN this case, the circuit breaker cannot be withdrawn or inserted by a rotational force of the lead screw 32, whereby the circuit breaker can be prevented from being withdrawn or inserted while being closed.
However, the related art apparatus for preventing withdrawing or inserting of the circuit breaker has the following problem. That is, a severe frictional contact is generated from respective components including the manipulation pin and the link member as the operation of clamping the nut is repeated, the respective components are deformed or damaged during the operation. This results in a defective operation of the apparatus for preventing withdrawing and inserting to allow the carriage to be withdrawn or inserted while the circuit breaker is being closed, causing severe damage to the device and a safety accident.